1. Drag and drop the reference file over the button titled "Import publications from BibTeX, RIS, Endnote XML or PDF files" which is located in the "Search online" tab in your Desktop Library. Once you drop the file in this tab, it will be added in your "All Publications" list.
2. You can use the Import Wizard from the colwiz main menu on the top left of your Desktop Library. In this window, select "RIS BibTeX, PDF, etc" tab. You will then be asked to "Select File". Locate the file in the resulting window and it will be added to your "All Publications" tab.
Note: For details on how to export an EndNote XML file from the EndNote Application and adding it to colwiz, visit this link.